Study Of Disk Coreless Permanent Magnet Synchronous Motor With Wedgy Airgap Based On Halbach

As one part of the national project 863(2004AA32G080), text concentrates on the design and magnetic field analysis of disk coreless PMSM with wedgy airgap based on Halbach. As a high performance servo-motor, there are many characteristics of low mass, compact structure, low noise, low moment of inertia, small electromechanical time constant, steady running status in low speed in the disk coreless PMSM with wedgy airgap. As a perfect driving device, it could be used in many fields, such as numerical control machine, robot, electric vehicle, home appliance and so on.To optimize the motor, disk coreless PMSM with wedgy airgap based on Halbach is developed in text, making good use of the outer diameter. The magnetic flux density of this motor is heightened to obtain better performance by changing the structure of airgap. The coreless PMSM with wedgy airgap is analyzed by FEM. The FEM analysis has been done to prove that the method reducing the open domain into the smallest domain can obtain the results approximate to the accurate results. So the intention of simplification is achieved.There are many differences in structure between the disk coreless PMSM with wedgy airgap and traditional PMSM. There are no cores in the magnetism circuit except PMs. Leak magnetism circuit is very complex especially when the structure of wedgy airgap adopted causes magnetism circuit asymmetric. The calculation method of the disk coreless PMSM is also different from the traditional one. Several typical formulas are given in the text. The design method of disk coreless PMSM with wedgy airgap based on Halbach array is summed up and CAD software is compiled. In the technics, many difficulties are solved such as the inner/outer rotor structure technics, the fixation of PMs, the winding's perfusion, orientation and installation. And the special technics equipment for the machining of the disc motor must be taken into account. At last, the sampling motors of 250W and 2500W are designed and developed. Much experiment is made to prove that the performance of the disk coreless PMSM with wedgy airgap is better than the traditional PMSM with same power.Because of the structure of coreless and the wedgy airgap, compared with the traditional PMSM, the mass is much lighter and the efficiency is higher and vibratory noise is obviously lowered. The disk coreless PMSM with wedgy airgap could be used in many fields, especially electric automobile, ship propeller, electric tool in hand, machine arm and so on.